The planes have powerful digital cameras, which officials worry could be used to help Moscow gather sensitive intelligence.

Russia is allowed to send surveillance jets over the US under the Open Skies Treaty, which allows 34 countries to conduct unarmed observation flights.

The aim of the 2002 treaty is to increase transparency about military activity and help monitor arms control.

However, US military and intelligence officials claim they fear Russia is taking advantage of the loophole.

Commander of the US Strategic Command, Cecil Haney, said: “The treaty has become a critical component of Russia’s intelligence collection capability directed at the United States.

“In addition to overflying military installations, Russian Open Skies flights can overfly and collect on Department of Defence and national security or national critical infrastructure.”

Former assistant secretary of state for the bureau of arms control, Steve Rademaker, told Congress that Russia has adopted a series of measures that are inconsistent with the treaty.

Undersecretary of state for arms control and international security, Rose Gottemoeller, told a hearing: “… one of the advantages with the Open Skies Treaty is that we know exactly what the Russians are imaging, because they must share the imagery with us.”

According to a State Department official, the treaty nations have not yet received notice of the Russian request.

The request comes amid heightened tensions between the US and Russia, particularly over Moscow’s actions in Syria and the Ukraine.

It will put the Obama administration in the situation of having to decide whether to let Russia use the high-powered equipment on its surveillance planes at a time when Moscow is failing to meet all its obligations under the treaty.